Segment, Geographic and Revenue Information (Net Revenues by Region) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Segment Reporting Information | |||||||||||
| Net revenues | $ 8,548 | $ 9,872 | $ 10,610 | $ 11,077 | $ 9,500 | $ 9,197 | $ 9,503 | $ 9,745 | $ 40,107 | $ 37,945 | $ 34,631 |
| Americas | |||||||||||
| Segment Reporting Information | |||||||||||
| Net revenues | 29,301 | 27,817 | 25,487 | ||||||||
| EMEA | |||||||||||
| Segment Reporting Information | |||||||||||
| Net revenues | 6,092 | 5,714 | 4,994 | ||||||||
| Asia | |||||||||||
| Segment Reporting Information | |||||||||||
| Net revenues | $ 4,714 | $ 4,414 | $ 4,150 | ||||||||